There is a need in the chemical, pulp and paper, refinery and dairy industries, and for road cleaners, the emergency services and plumbers and people who handle hazardous materials to be able to effectively and efficiently block cesspits and/or pipes of various drainage systems in circumstances of for example, a chemical or liquid spill or a gas leak so as to prevent or limit flow of the same into for example the water table.
In terms of chemical spillages or flood water, this has been achieved in the past either through the use of floating booms or lead weighted mats or the like designed to span the entrance to stormwater drains. Such conventional systems are clearly however of limited value.